docs: def do_GET(self):
          """ Handle a HTTP GET request. """
          # Example session:
          # in  : GET /wsapi/decrypt?otp=ftftftccccdvvbfcfduvvcubikngtchlubtutucrld HTTP/1.0
          # out : OK counter=0004 low=f585 high=3e use=03
          if self.path.startswith(self.serve_url):
              from_key = self.path[len(self.serve_url):]
  
              val_res = self.decrypt_yubikey_otp(from_key)
  
              self.send_response(200)
              self.send_header('Content-type', 'text/html')
              self.end_headers()
              self.wfile.write(val_res)
              self.wfile.write("\n")
          elif self.stats_url and self.path == self.stats_url:
              self.send_response(200)
              self.send_header('Content-type', 'text/html')
              self.end_headers()
              for key in stats:
                  self.wfile.write("%s %d\n" % (key, stats[key]))
          else:
              self.log_error("Bad URL '%s' - I'm serving '%s' (responding 403)" % (self.path, self.serve_url))
              self.send_response(403, 'Forbidden')
              self.end_headers()